Brief Answer:
In case persistent,other causes need to be excluded.

Detailed Answer:
Hi Tressymcceavy,

Thanks for the query. I have read it & understand your concern.
Stye is a pimple like swelling on eye lid, near eye lash it is caused by infection/ irritation/ inflammation ( due to foreign body,stress to eye - non corrected refractory error) of the oil secreting gland in the skin of eye lid. As a result there is increased sebum secretion from the gland & it blocks the gland to form pimple like swelling & get infected later on.
As you guess eye drops ( post dated or contaminated for forming crust) or contaminated eyeliner can cause it.
* Mostly stye disappears over a period of 7-10 days with use of antibiotic eye drops./ fomentation.
-In case it is persistent-it may be Chalazion-- which needs different treatment.
- It's worth excluding problems of vision causing stress to eyes..( cataract formation( age wise possibility/ Pressure problems in eye/refractory error or other eye pathological conditions of eye/ general weakness or conditions ike diabetes need to be corrected.
*Please consult an Ophthalmologist. for proper diagnosis & cause specific management.
I hope, you found the answer helpful. Any follow up query is welcome.
Thanks.

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